Weak Interaction of Ni-Doped SnO2 Powder Materials with Sodium Benzenesulfonate Homologues as Templates

Abstract

The tin oxide and the nickel-doped tin oxide photocatalyst were successfully prepared by the simple solid-state reaction among SnCl4·5H2O, NiCl2·6H2O and NaOH using sodium benzenesulfonate homologues as templates. The samples were characterized by X-ray powder diffraction (XRD), UV–Vis absorption spectra (UV–Vis), X-ray photoelectron spectroscopy (XPS) and N2 adsorption–desorption. The weak interaction between Ni2+ and templates in the reaction system was quantified, and the photodegradation properties of puerarin on the materials were estimated. The results show that Ni2+ enters the (110) crystal plane of SnO2, producing lattice distortion, as well as, the relative diffraction intensity (I101/ I110) change of the (101) and (110) crystal plane. And it squats in the lattice in the form of Ni2+ and Ni3+ to produce impurity energy levels, which reduces the band gap width (△Eg) of SnO2 from 3.4 to 3.02 eV. The weak interaction between surfactants and precursors (Ni2+ ions) is mainly derived from the steric hindrances of the sodium benzenesulfonate homologues of the size of the substituted groups, and the induction effect of Ni2+ ions. Wherein, the steric hindrance of surfactants plays a leading role, while the induction of Ni2+ ions plays a secondary role, the contribution of the steric resistance effect of ethyl and methyl for surfactants EBSS, STS to lattice mismatch is 0.23% and 0.14%, respectively, that is, the steric hindrance effect of methyl is only ~ 60% of that of ethyl. The greater the steric hindrance of the surfactants, the higher the lattice mismatch rate, the relative diffraction intensity (I101/I110), the oxygen defect concentration and the ratio of Ni2+/ Ni3+, the stronger the photodegradation ability of Ni–SnO2-EBSS material to puerarin is. In 50 min, the degradation rate of puerarin solution with initial concentration of 20 mg/L is 99.1%.